Re: Polaroid FLM323 Blue led, no video
Here's an update - six months later. At first, I thought the main board was faulty because I had proper voltages all around from the power supply. I ordered a pullout main board from Shopjimmy but the problem remained. It finally dawned on me that, although the voltages were OK, the board couldn't supply enough current. I set out to repair the power supply board and never succeeded - kept blowing up mosfets at $5.00 a pop. At any rate, I finally found a PSU on ebay for $30. I installed it and everything came on; perfect picture but no sound...
xyloeye
Member
Last Activity: 03-31-2020, 08:32 PM
Joined: 05-13-2011
Location: Anacortes, WA
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Re: Polaroid FLM323 Blue led, no video
I replaced the PFC (bulk) cap as well as the caps in the low voltage side and still the PFC boost voltage is around 220v and fluctuating. Also replaced all caps on the low voltage side just because they're cheap. I can still light up two series 1157's as Bud suggested, but they still flicker. Can't find any shorts in FET's, diodes, etc. What could cause the PFC voltage to be so low?Leave a comment:
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Re: Polaroid PSU output power
Oh, thanks, Bud. I didn't realize the boost was that much. I think I saw in another thread (could be mistaken) where you mentioned that the high voltage film cap is part of the 24v circuit. Is it necessary for proper function of the PFC?Leave a comment:
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Re: Polaroid PSU output power
Would the PFC boost voltage be that high (390) in the US where we start with 120VAC? tom66 is in the UK where it's 230VAC.Leave a comment:
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Re: Polaroid FLM-3232: Help Identify Diodes in PFC Cct
I sent you a pm (because the thread was old) a couple of weeks ago about the same problem you're having. I didn't see this thread, only the original. Anyway, I have the same psu with 24v present until I plug in the main board. Then the inverter voltage goes to .09v and the main board supply to 16v. I thought the main was fried so ordered a replacement from Shopjimmy. The new board didn't help. Now I'm thinking the psu is getting swamped by the load or maybe too much ripple. Haven't had a chance to get back to it. Did you ever...Leave a comment:
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Re: Polaroid PSU output power
I don't mean to hijack this thread, but I have the same problem in a Poloroid FLM323 that normally outputs only 24v. The 24v is present but plugging in the main board swamps the voltage down to 16v and the inverter supply goes to nearly zero. I think I've narrowed it down to the PFC also since the voltage across the big cap is only 170v. I'm wondering about a defective diode or maybe the PWM controller. I just got a couple of parts in and I'll report back if I figure anything out.Leave a comment:
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Re: Polaroid FLM323 Blue led, no video
Well, still no backlights but you got me to thinking about the PFC circuit. I measured the voltage across the high voltage cap again and got 220v, but fluctuating. The voltage also falls very quickly. I took the cap out and the esr is .5, probably 6 or 8 times what it should be. I have one on order from Mouser. I let you know if it fixes the voltage as soon as I get it. Thanks again, Bud
KenLeave a comment:
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Re: Polaroid FLM323 Blue led, no video
I might not be understanding some terminology. By PFC you mean power factor correction, right? How would I know if it's working? And do you mean to jump 24v through a 5K to the back light on pin?Leave a comment:
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Re: Polaroid FLM323 Blue led, no video
Yeah. I do have 4.9v going to the inverter bl-on coming through the funky
plug -in connector under the main board. I haven't checked the dim pin voltage. I got the replacement board from ShopJimmy so I assumed it was good. But it sure seems like it may be bad too.Leave a comment:
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Re: Polaroid FLM323 Blue led, no video
Right. 24 vdc on all pins until I plug in the main board then everything goes low. That's why I replaced the main originally. I thought it was swamping the output from the psu. The ps-on & dim signals on the inverter come from the main board so I don't have a source on the psu to turn it on from just the supply. It's frustrating.Leave a comment:
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Re: Polaroid FLM323 Blue led, no video
Here's the trace side....Leave a comment:
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Re: Polaroid FLM323 Blue led, no video
Power supply. My circles didn't show up. Upper left connector goes to main. Lower left to inverter....Last edited by xyloeye; 12-29-2013, 10:27 PM.Leave a comment:
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Re: Polaroid FLM323 Blue led, no video
I can't seem to get a picture to upload. I'll keep working on it.Leave a comment:
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Re: Polaroid FLM323 Blue led, no video
This supply: Polaroid 846-240-H3CZZSH
In my pictures, the red circles are to inverter and are all 24vdc. The blue circles are the main board connectors. Red wires are all 24vdc and the one blue wire is the 5v ps-on wire.Last edited by xyloeye; 12-29-2013, 10:15 PM.Leave a comment:
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Re: Polaroid FLM323 Blue led, no video
That's the weird thing. The main board receives only 24v. It's regulated to 5v and sent back to the ps-on pin. Main board supply is regulated down from the 24v on the board itself for its own supply as near as I can figure. Standby voltage in this thing is 24vdc!...Leave a comment:
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Re: Polaroid FLM323 Blue led, no video
That's the thing. There is 4.9v coming from the main board to the psu turn on pin. So I get about 1v to the inverter and 16v to the main board on the 24v pins. The only output from the psu (normally) is 24 volts, one connector to the main and another to the inverter. I think the only 5v standby supply comes from the main board and is regulated down from the 24 volts. So to turn on the inverter I think I have to use an external 5v supply.
I still have only 180v on the main cap when the psu is forced on.
I was also thinking...Last edited by xyloeye; 12-29-2013, 09:07 PM.Leave a comment:
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Re: Polaroid FLM323 Blue led, no video
I checked the 24v output with two 1157's in series. The voltage varies between 22.6 & 23.7. The bulbs flicker a little also. Bad regulation on the supply?Last edited by xyloeye; 12-29-2013, 07:30 PM.Leave a comment:
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Re: Polaroid FLM323 Blue led, no video
OK, thanks. I'll give that a try.Leave a comment:
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Polaroid FLM323 Blue led, no video
I have to ask for some help on this one. While I realize Polaroid TVs are not first rate, I need to understand what's going on with it. I can't find a schematic but from my understanding, the only voltage from the PSU is 24v. I have 24v until I plug the main board in. Then the voltage goes to around 1v to the inverter and 16v at the main board. This happens whether the turn on voltage from the main board (4.9v) is used or if I turn it on with a resistor. There is no voltage on the inverter turn on pin.
I thought the main board was pulling down the PSU so I ordered a pullout board... -
Eeprom corruption
I just tried to update the firmware on a Sony LCD TV and it apparently killed the TV. It got almost through the process and then just displays the Bravia logo. The amber picture led and red standby led stay on (no flashing). The only way to turn it off is by unplugging. There's no response to the remote. There's also no response to the reset sequence. I was updating because two of the HDMI ports stopped working. Can a failed firmware upgrade corrupt the eeprom with no way to recover? Does the main board have to be replaced? Any help would be appreciated. Thanks
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